I. Field of the Invention
The present invention relates to fastener delivery apparatus.
II. Description of Related Art
The term “fastener” is used herein to include rivets, screws, slugs, weld studs, mechanical studs and other types of fastening devices.
Known fastener delivery apparatus include a nose assembly into which a rivet is passed from a rivet storage location, and from which the rivet is inserted into a workpiece by an actuator. The nose assembly includes a central bore through which the rivet and the actuator travel before the rivet is inserted into the workpiece. The nose assembly further includes rivet retention means provided at a bottom end of the central bore, the rivet retention means acting to prevent the rivet from falling out of the nose assembly. The rivet retention means may for example comprise a plurality of balls or rollers which are resiliently biased towards the central bore such that they engage with the rivet when the rivet reaches a bottom end of the nose assembly. In addition to preventing the rivet from falling from the nose assembly, the balls or rollers assist in ensuring that the rivet has a desired orientation and is centralised in the central bore before the rivet is inserted into a workpiece.
Resilient biasing of the balls or rollers towards the central bore of the nose assembly may for example be provided by resilient rubber (or plastic) nose end-blocks located behind the balls or rollers (i.e. on an opposite side from the central bore), or may be provided by a Tensator (trademark) spring which extends around the nose assembly. Examples of both of these arrangements are described in European Patent EP0746431. In other known fastener delivery apparatus the Tensator spring is replaced by an O-ring which resiliently biases the balls towards the central bore in the same way as the Tensator spring.
It is desirable to be able to fasten workpieces together in a variety of different locations. It may for example be desirable to fasten together flanges which project from an object (for example a gutter which projects from a door window of a car) or some other workpiece which is located adjacent to an obstacle. A fastener insertion apparatus may be unable to fasten the workpiece unless the workpiece projects from the obstacle by a distance which is at least equal to (or substantially equal to) the diameter of the nose assembly of the fastener insertion apparatus.
It is desirable to provide a fastener delivery apparatus having a nose assembly which is narrower in at least one direction compared with at least some known prior art fastener delivery apparatus.